The study identifies the *ZmWAKL* gene as the causative gene for quantitative resistance to gray leaf spot (GLS) in maize. *ZmWAKL* encodes a cell-wall-associated receptor kinase-like protein that self-associates and interacts with the leucine-rich repeat immune-related kinase *ZmWIK* on the plasma membrane. The *ZmWAKL/ZmWIK* receptor complex phosphorylates the receptor-like cytoplasmic kinase *ZmBLK1*, which in turn phosphorylates the NADPH oxidase *ZmRBOH4*. Upon pathogen infection, *ZmWAKL* phosphorylation activity increases transiently, initiating immune signaling from *ZmWAKL*, *ZmWIK* to *ZmBLK1* and then to *ZmRBOH4*, ultimately triggering a reactive oxygen species (ROS) burst. The study reveals the role of the *ZmWAKL-ZmWIK-ZmBLK1-ZmRBOH4* module in perceiving pathogen invasion, transducing immune signals, activating defense responses, and conferring increased resistance to GLS.The study identifies the *ZmWAKL* gene as the causative gene for quantitative resistance to gray leaf spot (GLS) in maize. *ZmWAKL* encodes a cell-wall-associated receptor kinase-like protein that self-associates and interacts with the leucine-rich repeat immune-related kinase *ZmWIK* on the plasma membrane. The *ZmWAKL/ZmWIK* receptor complex phosphorylates the receptor-like cytoplasmic kinase *ZmBLK1*, which in turn phosphorylates the NADPH oxidase *ZmRBOH4*. Upon pathogen infection, *ZmWAKL* phosphorylation activity increases transiently, initiating immune signaling from *ZmWAKL*, *ZmWIK* to *ZmBLK1* and then to *ZmRBOH4*, ultimately triggering a reactive oxygen species (ROS) burst. The study reveals the role of the *ZmWAKL-ZmWIK-ZmBLK1-ZmRBOH4* module in perceiving pathogen invasion, transducing immune signals, activating defense responses, and conferring increased resistance to GLS.